package com.loubobooo.personal.blog.util;

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.codehaus.jackson.map.DeserializationConfig;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.SerializationConfig;
import org.codehaus.jackson.map.annotate.JsonSerialize;
import org.codehaus.jackson.type.JavaType;
import org.codehaus.jackson.type.TypeReference;

import java.io.IOException;
import java.text.SimpleDateFormat;

@Slf4j
public class JsonUtil {

    private static ObjectMapper objectMapper = new ObjectMapper();

    static{
        //对象的所有字段全部列入
        //NON_NULL只有非空的字段才会展示
        //NON_EMPTY对" "也作排空处理
        objectMapper.setSerializationInclusion(JsonSerialize.Inclusion.ALWAYS);

        //取消默认转换timestamps形式
        objectMapper.configure(SerializationConfig.Feature.WRITE_DATES_AS_TIMESTAMPS, false);

        //忽略空Bean转json的错误
        objectMapper.configure(SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS, false);

        //所有的日期格式都统一为以下的样式，即yyyy-MM-dd HH:mm:ss
        objectMapper.setDateFormat(new SimpleDateFormat(DateTimeUtil.STANDARD_FORMAT));

        //忽略（false） 在json字符串中存在，但是在java对象中不存在对应属性的情况。防止错误
        objectMapper.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES, false);
    }

    public static <T> String obj2String(Object obj){

        if(obj == null){
            return null;
        }
        try {
            return obj instanceof String ? (String) obj : objectMapper.writeValueAsString(obj);
        } catch (Exception e) {
            log.warn("Parse Object to String error",e);
            return null;
        }
    }

    /**
     * 返回格式化好的json字符串
     * @param obj
     * @param <T>
     * @return
     */
    public static <T> String obj2StringPretty(Object obj){

        if(obj == null){
            return null;
        }
        try {
            return obj instanceof String ? (String) obj : objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(obj);
        } catch (Exception e) {
            log.warn("Parse Object to String error",e);
            return null;
        }
    }

    public static <T> T string2Obj(String str, TypeReference typeReference){
        if(StringUtils.isEmpty(str) || typeReference == null){
            return null;
        }
        try {
            return (T)(typeReference.getType().equals(String.class) ? str : objectMapper.readValue(str, typeReference));
        } catch (Exception e) {
            log.warn("Parse String to Object error",e);
            return null;
        }
    }


    public static <T> T string2Obj(String str, Class<T> clazz){
        if(StringUtils.isEmpty(str) || clazz == null){
            return null;
        }
        try {
            return clazz.equals(String.class) ? (T) str : objectMapper.readValue(str, clazz);
        } catch (IOException e) {
            log.warn("Parse String to Object error",e);
            return null;
        }
    }

    public static <T> T string2Obj(String str, Class<?> clazz, Class<?>...elementClasses){

        JavaType javaType = objectMapper.getTypeFactory().constructParametricType(clazz,elementClasses);
        try {
            return objectMapper.readValue(str, javaType);
        }catch(Exception e){
            log.warn("Parse String to Object error",e);
            return null;
        }
    }

}